白皙嫩滑的手臂被抓得生疼的樱桃忍着手臂上的疼痛，不由得为陈源担心起来，且不说他是她心目中的好人，单是如今离了地下城，她还需要靠他生活呢，如果他这个时候出了什么事，她一个没甚见识，又没甚手艺的女人在这样一个从来没有来过的世界，如何能够生存下去？Dr. Steven Sorenson plans to tap the geothermal energy of the Earth"s interior by means of a thermonuclear device detonated deep within the Earth. Despite dire warnings by fellow scientist Ted Rampian, Dr Sorenson proceeds with the experiment after secretly learning that he is terminally ill. This experiment causes a crack to form and grow within the earth"s crust, which threatens to split the earth in two if it is not stopped in time.
